Yes. Breathing in someone else's cigarette smoke (passive smoking or secondhand smoking) can increase your risk of cancer and other health problems. It is also particularly harmful for children.

Yes. Breathing in someone else's cigarette smoke (passive smoking or secondhand smoking) can increase your risk of cancer and other health problems. It is also particularly harmful for children.

Smoke stays in the air

When someone smokes a cigarette, the smoke from the burning tip is released into the air. So is the smoke they breathe out. Smoke can stay in the air for up to 2.5 hours, even with a window open. It may still be there even if you can't see it or smell it.

This also applies in small enclosed places, such as cars. Smoke may still be present in large amounts even after the person has stopped smoking.

Risks of passive smoking

Passive smoking can damage your body because secondhand smoke contains more than 4,000 chemicals, many of which are irritants and toxins, and some of which are known to cause cancer. Passive smoking from all forms of tobacco is harmful, including:

Children who grow up with a parent or family member who smokes are three times more likely to start smoking themselves.

If you're a parent who smokes, it will be hard to explain to your children why they shouldn't start smoking. Try to lead by example and quit. As well as improving your health and theirs, your children may be less likely to start smoking later in life. See below for where to get support.

Smoking and the law

In July 2007, smoking in public places such as bars, restaurants and workplaces was made illegal to protect non-smokers from the health risks associated with passive smoking.